1. Field of the Invention
The present invention relates to a mail server for delivering electronic mail addressed to a mobile communication terminal to the mobile communication terminal, a mobile communication terminal for receiving the delivered electronic mail.
2. Related Background Art
In recent years, with the development of information communication technology, it has become common for electronic mail to be transmitted and received using mobile communication terminals such as portable telephones. In an electronic mail system using a mobile communication terminal, an electronic mail that is transmitted from a transmission source terminal to a mobile communication terminal serving as a transmission destination terminal is received in a reception side mail server, and automatically delivered from the reception side mail server to the mobile communication terminal. As a result, the user of the mobile communication terminal may read the electronic mail that has been delivered to the mobile communication terminal whenever s/he wishes.
However, when the mobile communication terminal is unable to receive electronic mail, for example when the mobile communication terminal is in a location at which radio waves cannot be received or when the power of the mobile communication terminal has been switched off, the reception side mail server does not deliver the electronic mail to the mobile communication terminal and the electronic mail is stored in the reception side mail server. Hence when an urgent electronic mail is sent, the sender does not know whether the electronic mail has been delivered, and since the sender does not know whether the electronic mail has been received in the mobile communication terminal, the sender may have to send the same mail many times. Moreover, the receiver can only learn that a mail is being stored by making an enquiry to the reception side mail server or waiting for the arrival of the next mail.
Systems and the like are known for dealing with this type of problem (for example, Japanese Unexamined Patent Application Publication 2001-156830). In such systems, the receiver side is notified when a mobile communication terminal cannot receive electronic mail, and when the mobile communication terminal becomes able to receive electronic mail, electronic mail is delivered to the mobile communication terminal.